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Article: Preparation and properties of thienyl and 2,2'-bithienyl substituted cobalt-bis(semiquinone) valence tautomers.(Report)
- Article from:
- Canadian Journal of Chemistry
- Article date:
- April 1, 2009
- Author:
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Introduction
Valence tautomerism (VT) in cobalt(II) coordination complexes containing 2,2'-bipyridine and semiquinone anion-radical ligands was discovered in 1980 by Pierpont and Buchanan. (1) These fascinating molecular materials feature dynamic electronic structures that can switch between different electronic states as a result of a similarity in the frontier orbital energies of cobalt(II) and the coordinated semiquinone. In particular, an intramolecular electron transfer reaction results in the formation of cobalt(Ill)-catecho late species, and accompanying the cobalt(II)-to-semiquinone electron transfer is a change in spin state of the cobalt ion from high ...